Pattern for dental plates.



I. PETRYI PATTERN FOR DENTAL PLATES. APPLICATION FILED NOV. 8. I915.

1 74,322. Patented July 30, 1918.

2 SHEETS-SHEET I I FIG.1 FIG.3 FIG.5

WITNESSES.

J. PETRY.

PATTERN FOR DENTAL PLATES.

APPLICATION FILED NOV. 8. 1915.

1 ,274,322. Patented July 30, 1918.

2 SHEETSSHEET 2.

FIG.13 FIG. 14

FIG.15 FIG. 16

wrrNEssEs INVE OR UNITE STATES PATENT OFFICE.

JACOB PETRY, 0F PITTSBURGH, PENNSYLVANIA.

PATTERN FOR DENTAL PLATES.

Application filed November 8, 1915.

To all whom it may concern Be it known that I, J Acon Pn'rnr, a citizen of the United States, and resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Patterns for Dental Plates; and I do hereby declare the following to be a full, clear, and exact descri tion thereof.

N y invention relates to patterns for dental plates and is particularly concerned with a pattern for a plate having an undercut cavity or socket for the reception of a suction retainer such as that shown in my Patent No. 1,005,296, dated the 10th day of October, 1911.

One of the main objects of my present invention is to insure in the finished plate, that the bottom of the socket which receives the suction retainer shall be at all points equal distances from the upper face of the plate, not only along the rim of the overhanging lip which overlaps the edge of the suction retainer, but also throughout the entire area of said socket, so that when the suction retainer is secured in position in this receiving socket of the plate, said retainer will conform exactly to the contours of the roof of the mouth when the plate is in position.

Different expedients have been resorted to heretofore for securing this uniformity in the bottom of this socket, but in every case the plate is originally distorted from its proper contour or becomes so when the suction retainer is secured to it. Or, if the bottom of the socket is not distorted, the lip or rim over-lying the edge of the suction retainer is frequently distorted in the effort to remove the molding material from the socket of the molded plate.

In the practice of my invention, I construct the pattern out of plastic material, preferably wax, and in at least two layers. With the plastic layers I employ pattern plates of pliable material for the formation of the pattern of the socket in the plastic material. From this plastic pattern a mold is formed in the manner hereinafter to be described.

For the purpose of a clear understanding of the invention, the various steps in the method are raphieally illustrated in the accompanying drawings in which Figure 1 is a perspective view of a plaster cast of the Specification of Letters Patent.

Patented July 30, 1918.

Serial No. 60,351.

roof of the mouth. Fig. 2 is a transverse section thereof on the line 22. Fig. 3 is a view similar to Fig. 1, showing the first socket pattern plate in position. Fig. 4 is a transverse section on Fig. 3. Fig. 5 is a view showing the first .layer of plastic material molded to the cast around the socket pattern plate. Fig. 6 is a section on the line (30, Fig. 5. Fig. 7 shows the second socket pattern plate on the cast, Fig. 5. Fig. 8 is a transverse section on the line 88, Fig. 7. Fig. 9 is a perspective view of the first plastic pattern layer. Fig. 10 is a similar view of the second plastic pattern layer. Fig. 11 is a perspective viewof the plastic pattern assembled. Fig. 12 is a sectional view of the pattern. Fig. 13 shows the plastic pattern incased in a mold flask with a molding material surrounding the same. Fig. 14. is a view similar to Fig. 10 illustrating the mold cavity left by the pattern. Fig. 15 is a plan view of one of the mold sections showing the arrangement of the pouring or blow holes. Figs. 10 and 17 are perspective and sectional views respectively of the completed metal dental plate.

In the embodiment of the invention herein illustrated, the plaster cast 1 shown in Fig. 1 is given the contour of the roof of the mouth throughout the area 2 by the usual method of taking such impression, and it is the object thereafter that the mold for the dental plate shall conform exactly to these contours in its finished form. Ordinarily, it is a simple matter to produce a pattern for the dental plate from such plaster cast, but with a dental plate of the peculiar eonstruction, having the peculiar form of Sue tion retainer illustrated in my companion patent above referred to, it is necessary that this suction retainer throughout its area shall follow accurately the contours of that surface of the dental plate which has been so shaped. It is necessary to form within the dental plate a cavity or socket to receive the securing foundation portion of the suction retainer, and this socket must therefore be provided with an over-lying lip extending throughout the perimeter of the socket. The edge of this lip must remain of the exact contour of the corresponding portion of the roof of the mouth, and the bottom of the socket must conform accurately to the shape of that portion of the roof of the month which overlies the socket, but ebvious ly, the bo'ttom of the socket will be re moved some :little tl istance from the nor- .mal plane or planes of the upper face of the =finished plate, in order to provide clearance for the suction retaining member between the bottom of the'socket and the roof of the ,in such plate in exact conformity with that portion of the roof of the mouth which overlies the socket. Many expedients have been tried, but none heretofore in my experiencehave been successful,'for the reason thatv the over-hanging lip of the socket is almost invariably distorted when the pattern is filled in the mold flask, or when the pattern is being removed therefrom, or finally, when the molded plate-is removed from the pattern. p

In order to overcome these difliculties, I form the pattern itself of two superposed layers of material, in one of which the opening and outline of the socket lip is formed, and on the other the contours of the base of the socket. on accurate molding, I "employ plastic material for the pattern and for a purpose hereinafter described, I prefer to employ easily fusible'ma'terial, such as .wax. The members for forming the socket and opening in the pattern, over, and around which the plastic material orwax maybe shaped, must be of pliable material, in order that they may conform exactly to the contours of the'roof of'the mouth overlying the socket opening, and overlying the overhanging lip of the-socket. 1 1

Referring to the drawing, '1 first place upon the molded face of the plastercast a thin plate 3, of pliable materiahsuch as tin foil, tissue paper, or like materiahavhich' is pressed down hard againstthe molded face to cause the same to conform exactly to its contours; A layer of plastic material which, I shall hereafter refer to as wax is then placed over the molded face of the cast pletes the molded surface of the upper face ofthe pattern, or that face which conforms exactly to the contours of the roof of the mouth, as determined by the plaster cast.

The opening formed in this first wax layer 4 conforms exactly to the shape of the suction retaining member, or so much thereof as is to be exposed to the roof of the mouth. This suction retaining member, however, is fastenedin place by means of a projecting lip or lateral extension of its base or foundation member and may be cemented thereto; therefore, the socket in the dental plate "must have anundercut cavity to receive this suction retainer fastening lip. In this is presented the problem which this invention inthe'mai'n is intendedto solve. Referring to Fig. 7 it will be seen that a secondplateS, symmetrical in outline with the plate'3, but of larger area, is placed upon said plate 8 and is pressed firmly down upon said plate, so'that it will partake exactly of the moldedcontour of this plate-3, which'as before described, conforms to the contours of the molded faceQ of the plaster cast 1.

A second layer of wax such as'G, Fig.8, is thenunolde'd over the plate 5 and-over the exposed rim 4 ofthe first wax layer. Thus it will' b'e seen that portionof the wax layer 6 adjacent the face 7 of the plate 5, will form the bottom of the socketin-"the finished pattern'fand this bot-tom face of the socket willnecess'arily follow accurately the contoursof tlieroofof'the mouth throughout the area of the plaster cast underlying the plate? 'At the same timefth e portion of the first w'ax layer 4 extendingbeneath the edges ofthe plate '5 will form -a lip 8 surrounding the suction retainer opening in the pattern and-the space beneath the lip 8 forms the undercut cavity-for the reception of the projecting securing lip ofthe foundationor backing of the suction retainer.

Before placingthe'upperlayer 6 of wax over the plate 5, and thewax layer eythe and 6 and theplates 3 and 5, so that the parts may be readily'separated for the re moval of the shaping plates 3*and' 5. Fig. 9' and Fig. 10 show these wax layers separated and the plates 3 and 5removed. The

two wax layeis are then placed together again, and produce the complete pattern in wax that'is shown'm perspective face view, Fig. .11, and in sectlonal view, Flg. 12,

wherein the' suction retaining cavity or socket is clfearly apparent, said socket having'the bottom 9 conforming exactly tothe contours of the plaster cast 2, the retaining rim 8 which 'also'conforms exactly 'to the contour of the roof of the mouth, and forms the undercut portion 10 for the reception of the securing part of'the suction retainer.

7 For thetpurpose of forming from this pattern the moldforthe dental plate, the socket or the'cavity is first filled with material in semi-fiuid state, which completely fills the cavity, including the undercut portion 10 and by reason of its fluid conditions, extends into the inmost recesses of said eavity. The use of a camels-hair brush brush ing the soft investment compound underneath the flange, and tapping mold may be advisable.

One half of the mold flask 11, Fig. 13, is filled to the proper depth with the molding material 12, and the pattern is laid upon this n'iaterial and impressed into it. The other half 13 of the flask is also filled with the molding material 12 and filled in against the wax pattern and the filled portion of the cavity. The mold is then provided with the usual blow hole l t and pouring hole 1.5, and the two sections are clamped together in the usual manner. The mold is then heated for the purpose, not only of drying out the mold material, but also melting out the wax pattern which is absorbed by the mold material, leaving the mold cavity entirely clear. This melting out of the wax has also the advantage that it fills up the pores of the mold material around the mold cavity, leaving a smooth, clean-cut surface for the production of the molded dental plate. The molten metal from which the plate is to be formed is then poured into the mold in the usual manner; the sections of the mold flask are then separated, and the molded dental plate 16 removed therefrom. All vestige of the molding material is then cut out or otherwise removed from the suction retaining cavity or socket 17 and particularly from the under cut cavity 18. It will be seen, therefore, that the molded face 19 of the plate will conform exactly to or will be a reproduction of the molded face 2 of the plaster cast 1, and the edge 20 of the lip 21 overlying the perimeter of the cavity or the socket, will likewise conform throughout, to the contours of the roof of the mouth. The cross section of the undercut cavity 18 of the socket, is exactly the same as that of the securing rim or lip of the suction retainer. The latter, therefore, may be inserted within this cavity, and secured in place in any desired. manner, as by cement, and the suction retaining portion of the suction retainer will extend into the opening in the inner face of the plate, and by reason of the fact that the bottom 22 of this cavity corresponds througlmut in contour with the contour of the opposite portion of the roof of the mouth, it is obvious that the suction rctainer will be held in a shape likewise to conform. Hence, there will be no uncomfortable or irritating projection of the suction retainer above the inner face of the dental plate.

While I have herein described a particu lar embodiment of the invention, and a particular method of carrying the same into effect, it is to be understood that the invention may be altered in details and arrangement of parts, within the scope of the appended claims.

lVhat I claim is:

1. A molding pattern for articles having an undercut cavity therein, con'iprising a layer of more or less readily fusible ma terial, having an opening therein conforming to the opening of the cavity, a second layer of similar material having a recess therein of an area equal to the greatest area of the cavity, said layers being superposed one upon the other.

2. A molding pattern for articles having an undercut cavity therein, comprising a layer of more or less readily fusible material, having an opening therein conforming to the opening of the cavity, a second layer of similar material having a recess therein of an area equal to the greatest area of the cavity, said layers being superposed one upon the other, and a coating of lubricating material between the layers.

3. A molding pattern for articles having an undercut cavity therein, comprising a layer of more or less readily fusible material, having an opening therein conformmg to the opening of the cavity, a second layer of similar material having a recess therein of an area equal to the greatest area of the cavity, said layers being superposed one upon the other, the exposed face of the first layer being shaped to conform exactly to one face of the articles, the portion of the other layer forming the cavity shaped to parallel in all its contours a predetermined shape of the article which said ex posed face of the first layer is intended to fit.

4. A molding pattern for articles having an undercut cavity therein, comprising a layer of more or less readily fusible material, having an opening therein conforming to the opening of the cavity, a second layer of similar material having a recess therein of an area equal to the greatest area of the cavity, said layers being superposed one upon the other, the exposed face of the first layer bein" shaped to conform exactly to one face of the article, the portion of the other layer forming the cavity shaped to parallel in all its contours, a predetermined shape of the article which said exposed face of the first layer is intended to lit, the exposed face of the second layer being shaped to predetermined form.

A pattern for dental plates couiprising a layer of easily fusible, plastic material, shaped to conform to the roof of the mouth, and having an opening therein adapted to receive a suction retainer, a second layer of similar material shaped to conform to the first, and having a recess of greater area adapted to lie opposite the opening in the first layer, the bottomof said recess being shaped to parallel in all its contours, the contours of that portion offthe roof of the mouth opposite Which it is intended -to lie, said opening and recess forming an undercut cavity for the reception and securing of a suction retainer.

6. A pattern for a dental plate composed of separable layers, of plastic, easily fusible material, superposed one upon the other, one having an opening therein, and the other a recess oppositeaand of greater area than said opening, to form an undercut suction retainer cavity Within said pattern.

7. A pattern for a dental plate composed of separable layers, of plastic, easily fusible material, superposed one upon the other, one having an opening therein, and the other a recess opposite and of greater area than'said opening, to form an undercut suctiont retainer cavity Within said pattern, the bottom of said cavity paralleling in all its contours that portion of the roof of the mouth opposite which it is intended to lie.

8. A pattern for a dental platecomposed of separablelayers, of plastic, easily fusible material, superposed one upon the other, one having an opening therein, and the other a recess opposite and of greater area than said opening, to form an undercut suction retainer cavity Within said pattern, means interposed between said layers, whereby they maybe easily separated.

Intestimony, I the said JACOB =PETRY, have hereunto set my hand.

J OHN F. WILL, J. R. KELLER.

Gopiea-ofi this patent may be obtained forrfive cents each,by addressingthe' Commissioner ofll'atenta.

.washington D. C. 

